It is unclear whether arterial stiffness predicts the outcome of patients with acute ischemic stroke. We aimed to assess the prognostic value of arterial stiffness in this population. We studied 280 consecutive patients (37.5% males, age 78.8±6.4 years) who were hospitalized in our Department for acute ischemic stroke between September 2010 and May 2012. Arterial stiffness was assessed by measuring the augmentation index (AIx), central systolic blood pressure (cSBP) and central pulse pressure (cPP) over the radial artery with the Sphygmocor device. The severity of stroke was assessed with the National Institute of Health stroke scale (NIHSS) score at admission and the outcome was assessed with the modified Rankin scale score at exit from the hospital. None of the indices of arterial stiffness correlated with NIHSS score at admission. AIx showed a negative correlation with the modified Rankin scale score at exit from the hospital (r=−0.200, p<0.05). cSBP and cPP correlated with the number of days of hospitalization (r=0.180, p<0.05 and r=0.225, p<0.05, respectively). Twenty-five patients (8.9%) died during hospitalization. These patients had lower AIx than patients who were discharged (18.2±11.3 vs. 29.9±9.8, respectively; p<0.005). Other indices of aortic stiffness did not differ between patients who died during hospitalization and those who were discharged. In conclusion, a higher AIx was associated with better functional outcome and lower mortality rate in patients with acute ischemic stroke. Competing causes of death and the relatively beneficial effect of elevated BP during the acute phase of stroke might partly explain this apparently paradoxical finding.